Visible Light Induced Rhodium(I)‐Catalyzed C−H Borylation

Abstract

Abstract An efficient visible light induced rhodium(I)‐catalyzed regioselective borylation of aromatic C−H bonds is reported. The photocatalytic system is based on a single NHC−Rh I complex capable of both harvesting visible light and enabling the bond breaking/forming at room temperature. The chelating nature of the NHC‐carboxylate ligand was critical to ensure the stability of the Rh I complex and to provide excellent photocatalytic activities. Experimental mechanistic studies evidenced a photooxidative ortho C−H bond addition upon irradiation with blue LEDs, leading to a cyclometalated Rh III ‐hydride intermediate.